The hydrostatic principle is well known in the prior art. An example of the hydrostatic principle is in a liquid container provided with an outlet in the form of a suction pipe. In situations where there is no outtake from the container the liquid in the suction pipe will either run back into the container and thereby create a vacuum for containers placed underground, or the pressure will be equal to the pressure inside the container for containers placed above ground. The relationship between vacuum/pressure and liquid level in the container is linear. So in an underground container the vacuum in the suction pipe will increase as the liquid level in the container decreases. At the same token the pressure in a container will increase as the liquid level in the container increases.
JP 59-023750 (abstract only) describes the measurement of the liquid level in an underground tank. Here the measurement of a product level of a liquid is performed when there is no outtake from the container. This means that an apparatus is measuring the level of liquid in periods when the suction pump is not running by measuring directly on the pump and/or flow meter and/or control unit for these entities.
Conventional level reading techniques provide the problem of being time consuming to install and needing skilled fitters to carry out the installation. Thus, conventional level reading techniques are very expensive to use for the world market.
The present invention provides for the liquid level of a container to be determined in a cost efficient and time reducing manner by disclosing a level reading installation using the hydrostatic principle having less complicated hardware and being capable of installation without expert knowledge of areas, such as heat burners or the hydrostatic principle.